Abstract/Summary

Currently in the UK road surfaces are monitored visually for defects and signs of failure. However the time between detection of road degradation (e.g cracks and potholes), and complete failure of the road surface is very short. Therefore rejuvenation techniques that may initially be favourable are ineffective and a total resurfacing is the required. It is therefore of interest to be able to predict the condition of the road surface in an attempt to better plan and schedule the rejuvenation techniques and effectively save money, and maintain safer, more comfortable roads. Road surfaces can fail in many different ways as a result of many different factors. The chemical oxidation of bitumen, the main binding component of asphalt road surfaces, is a major contributor to the age hardening and ultimate failure of the roads. There is an abundance of research in the literature that has identified the use of infrared spectroscopy as an analytical technique to monitor the oxidation of bitumen and therefore this research looks to explore the feasibility of utilising this technique as a detection method for the oxidation of bitumen within asphalt road surfaces. Diffuse reflectance infrared spectroscopy has been utilised in this project in order to identify any possible oxidation product markers present within the infrared spectra collected. The project initially involved ageing bitumen artificially and naturally and analysing the changes with Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy. Once chemical oxidation markers had been identified the project then focused upon the artificial and natural ageing of asphalt. The same chemical markers were identified and quantified with regards to the solar exposure. Mechanical testing of bitumen and asphalt has also been carried out in order to compare the chemical changes to standardised physical property changes that correspond to deterioration of the bitumen. The project also develops a method for analysis of real road surfaces outside of the laboratory. A trolley has been built in order to support a handheld spectrometer close to the surface for data collection. A number of different roads have been analysed in this way. This report will outline the results obtained from these experiments and the data analysis. The recommendations and future work are also included within this report.